1. Field of the Invention
This disclosure relates generally to the field of video distribution over a network, and in particular to a scheduling apparatus and method for providing near video on demand over a distribution network.
2. Description of Related Art
When using a near-video-on-demand (NVOD) system, a user such as a subscriber has the opportunity to purchase or rent videos such as movies, including recent hit movies, using a broadcast technique known as staggered start. In a staggered start video distribution, a plurality of video signals, each of which corresponds to a single movie, is transmitted on multiple channels, with the beginning of each video signal starting at a different time. For movies with fixed play times, such different start times effectively stagger the movies by a short amount.
For example, the staggering time may be about fifteen minutes. Without staggering, a user has to wait for a movie to finish, which may be over two hours. Using staggering, a user waits, at most, only fifteen minutes; that is, the stagger time. For typical movies lasting about two hours (120 minutes), a staggered video distribution needs about 120 minutes/15 minutes of stagger time per channel=eight channels. Using multiplexing techniques, a plurality of staggered movies may be interleaved to transmit over the at least eight channels.
NVOD systems typically use a back-end processing system which initiates and coordinates NVOD video scheduling, as well as performing remote schedule retrieval, schedule validation, schedule error handling, schedule distribution, video service content management, event process modification, and downstream digital channel allocation. Such operations are typically used for other digital broadband services, such as video on demand (VOD), home shopping, and video conferencing.
Video distribution systems in the prior art implement VOD and NVOD, as well as staggered video distribution. For example, video distribution systems for storing, managing, and transmitting videos to a plurality of subscribers are described in commonly assigned U.S. Pat. No. 5,168,353 to Walker et al.; U.S. Pat. No. 5,311,423 to Clark; U.S. Pat. No. 5,383,112 to Clark; and U.S. Pat. No. 5,583,937 to Ullrich et al., which are incorporated herein by reference. Typically, such video distribution systems have a master scheduler connected to a video server, a billing computer, and optionally a downstream controller. The master scheduler sends a schedule in the form of, for example, a schedule file or database, to the video server, which in turn responds to the schedule to distribute videos.
Heretofore, such scheduling has been limited to scheduling videos and transferring billing and customer requests to the video server. Other aspects of a video distribution system have generally not been automated, with various independent systems handling specific operations without coordination.
A need exists for a video distribution system to provide operational support for an NVOD system, for example, to track the head-end configuration; to perform schedule revision, management and distribution; and to perform asset and content management.